87 Instrument Cluster Question

87-89 were the same. 90-93 are the same.

89+ V8 cars had the 140 mph speed. the 89 clusters are valuable because they have the 140 speedo and fit the nonair bag cars, the 90+ clusters will clear the airbag colums, but not fit an airbag car.

its hard to say what your issue is, could be wiring, the cluster, or multiple things. i would try to find an 87-89 cluster to try first, a known good one. they are easy to spot because they have the flat bottom, air bag clusters will have a half moon missing out of the bottom.

Speedo needle bounce at low speeds: you need to lubricate or replace the cable.

Speedometer Speedometer cable replacement for 87-93 Mustangs.

Note: All 89-93 cars have a VSS sensor even if they do not have cruse control. The 87-88 only have a VSS sensor if the have cruse control.
Speedo cable housing assembly without cruse control:


The VSS equipped cars have a speedo cable with a different fitting on the transmission end of the cable. It is the fitting on the LH side of the following picture.

Speedo cable housing assembly with cruse control


1. Inside the car:
1.) Remove the shield around the steering column that covers the ignition switch & turn indicator switch.
2.) You now have access to the two screws that hold the lower part of the cluster housing in place. Remove them and place them in a zip bag.
3.) Use a stubby or an offset Philips screwdriver to remove the two screws on the top of the cluster housing. The screws are up close to the windshield, so they can be hard to get at.
4.) The cluster housing will now slide forward: depending on your particular car, you may or may not have to disconnect the wiring for the headlights, hazard lights, or cluster wiring. All of the wiring uses plastic connectors with plastic spring clips on them. To release the connectors, lift the plastic clips and pull straight back.
5.) The speedo cable is secured in the speedo head by a white plastic clip. Depress the clip or squeeze it and pull the cable out of the speedo head. This can be tricky, but it will come out if you have the white clip depressed enough.

Photo courtesy of ALMOST STOCK


6.) With speedo cable removed from the speedo head, try twisting the cable end with your fingers. If it turns more than 1/4 turn, the cable may either be broken or you have damage at the other end where the cable mates to the VSS sensor or speedo pickup gear in the transmission.

2. Outside the car, replacing the cable housing assembly. The following steps are necessary only if you plan on replacing the cable & cable housing assembly.
7.) If you are going to the replace the cable housing, the next step is important. Tie a study string or wire to the VSS sensor end of the cable housing. This string or wire is to be used to fish the cable housing back through the maze of wires that is under the dash. If all you are going to do is replace the inner cable, you can omit this step.
8.) Jack up the car, all 4 tires must be off the ground. Place jackstands under the car for safety.
9.) Locate the VSS sensor on the driver’s side of the transmission tailshaft housing. The speedo cable housing will be secured in the VSS sensor with a hairpin clip Do not remove the clip!!!: The hairpin clip stays in place. If you remove it, the odds are that you will not be able to get the cable to stay in place on re-installation. Pull firmly straight back on the cable housing and it will come out. A considerable amount of effort may be required to get the cable out of the VSS sensor, but it will pull out.
10.) Release the cable housing from the clips that secure it to the car body.

3. Inside the car:
11.) The housing assembly can then be pulled out and the fish string or wire can be removed from the old cable housing and secured to the new one.
12.) The inner cable can be removed by pulling it out of the housing assembly. Watch out for the lubricant so that you don’t get it on the car’s interior.
13.) Lubricate only the lower part of the new cable with speedometer lubricant or graphite. Don’t use too much lubricant, or it will work its way up into the speedo head unit and damage it. Thread the inner cable into the housing, turning it as you go. When you are all the way in with the new cable, it will engage the VSS sensor and stop turning.

4. Outside the car, replacing the cable housing assembly. The following steps are necessary only if you plan on replacing the cable & cable housing assembly.
14.) Use the fish string or wire to feed the cable housing assembly through the dash wiring and out the cable hole in the firewall.
15.) Secure the cable in the body clips, making sure that the cable isn’t rubbing against the exhaust pipe.
16.) Push the cable housing assembly into the VSS sensor until it snaps in past the hairpin clip.

5. Inside the car:
17.) Push the cable housing back into the speedo head unit. You should be able to feel the white clip click into place.
18.) Reconnect all the wires & connectors on the speedo head unit.
19.) Re-install the cluster unit in the dash & tighten the 4 screws that hold it in place.
20.) Re-install the cover for the ignition switch & turn signal.
21.) If the car is up on jackstands, start the car, place it in gear & watch the speedo to see if it works OK. If you didn’t jack the car up, take a test drive.


The gas gauge has an anti slosh module that sometimes fails. When it does, the gauge will read off scale full until the level in the tank drops to about 2-3 gallons.

Use a DVM to check the voltage at the battery with the engine running. Compare your readings with the dash gauge. The middle mark on the dash gauge is supposed to be 14 volts.

Im pretty sure that the 89 was the cutoff.90 and newer mustangs have different plugs,or the wiring is different then the 89's.I have an 89 cluster floating around the back seat of my car.DO you need it or would you like one from a 4 cyl car.Let me know,i can have it tonight and ship it to you.I just installed an Mc-machine dash in my coupe and just went threw this hole instrument cluster wiring deal.Let me know if i can help.

wolf39us said:

I should have setup my profile

I have an

87 Mustang GT w/ T-tops V8
302 HO (I think its a 302 anyway)

a new cluster I found at Mustangs Unlimited that I was interested in
http://www.mustangsunlimited.com/itemdy00.asp?T1=M8987+01

and how much would you like for the cluster...I may use it for testing purposes

Click to expand...

Yes, that one is a complete cluster, ready to plug in. However, as mentioned above, you should really find out exactly what your problems are. Throwing a $400 cluster at your car when you could very well have other issues will mean you end up with a new cluster doing the same things.

Never just throw parts at your car without properly diagnosing the problem FIRST, you usually end up wasting money.

Send me your Email address and I will send you a zipped wiring diagram set for an 89 Mustang. The diagram zip file is too big to fit through Stangnet's email gateway. You'll need WinZip or RAR to upzip the files.

The body wiring will be the same as the 87. The engine and computer wiring will be different. There aren't any interconnects between the computer and instrument panel except the Check Engine Light, and that is a very minor thing.

I have a similar problem with my 1987 5.0 Mustang GT the battery gauge works fine but the oil, fuel and coolant gauges seem to get power because they move a little but dont display my stats correctly where can i buy a new icvr (instrument cluster voltage regulator) for my car?

So I think what you are after is the anti slosh module.

Not sure about the 87, but my 79-83 cars still have an instrument voltage regulator iirc, that cuts voltage to the gage sending units to 5 v or so. If it fails a couple gages will read weird. Also check the plugs and receptacles where they plug into the gage unit. Also, multiple gage issues may point to a ground issue.

86 was the last year for the icvr. 87-89 have the anti slosh module and 90 and up don’t have it.